Process for arylamine production

ABSTRACT

A process for synthesizing acrylamine compounds is provided. The process includes producing a dicarboxylic acid salt of an arylamine molecule by reacting a dicarboxylic acid arylamine with an alkyl salt to produce the dicarboxylic acid arylamine salt.

BACKGROUND

This disclosure relates generally to improved chemical processes for thesynthesis of arylamine compounds, and to the use of such arylaminecompounds in producing overcoating layers for electrophotographicimaging members. In particular, this disclosure provides a method forproducing a dicarboxylic acid salt of an arylamine molecule by reactinga dicarboxylic acid arylamine with an alkoxide salt to produce thedicarboxylic acid arylamine salt.

In electrophotography, an electrophotographic substrate containing aphotoconductive insulating layer on a conductive layer is imaged byfirst uniformly electrostatically charging a surface of the substrate.The substrate is then exposed to a pattern of activating electromagneticradiation, such as, for example, light. The light or otherelectromagnetic radiation selectively dissipates the charge inilluminated areas of the photoconductive insulating layer while leavingbehind an electrostatic latent image in non-illuminated areas of thephotoconductive insulating layer. This electrostatic latent image isthen developed to form a visible image by depositing finely dividedelectroscopic marking particles on the surface of the photoconductiveinsulating layer. The resulting visible image is then transferred fromthe electrophotographic substrate to a necessary member, such as, forexample, an intermediate transfer member or a print substrate, such aspaper. This image developing process can be repeated as many times asnecessary with reusable photoconductive insulating layers.

Image forming apparatus such as copiers, printers and facsimiles,including electrophotographic systems for charging, exposure,development, transfer, etc., using electrophotographic photoreceptorshave been widely employed. In such image forming apparatus, there areever increasing demands for improving the speed of the image formationprocesses, improving image quality, miniaturizing and prolonging thelife of the apparatus, reducing production and running costs, etc.Further, with recent advances in computers and communication technology,digital systems and color image output systems have been applied also toimage forming apparatus.

Electrophotographic imaging members (i.e. photoreceptors) are wellknown. Electrophotographic imaging members having either a flexible beltor a rigid drum configuration are commonly used in electrophotographicprocesses. Electrophotographic imaging members may comprise aphotoconductive layer including a single layer or composite layers.These electrophotographic imaging members take many different forms. Forexample, layered photoresponsive imaging members are known in the art.U.S. Pat. No. 4,265,990 to Stolka et al., which is incorporated hereinby reference in its entirety, describes a layered photoreceptor havingseparate photogenerating and charge transport layers. Thephotogenerating layer disclosed in the 990 patent is capable ofphotogenerating holes and injecting the photogenerated holes into thecharge transport layer. Thus, in the photoreceptors of the 990 patent,the photogenerating material generates electrons and holes whensubjected to light.

More advanced photoconductive photoreceptors containing highlyspecialized component layers are also known. For example, multilayeredphotoreceptors may include one or more of a substrate, an undercoatinglayer, an intermediate layer, an optional hole or charge blocking layer,a charge generating layer (including a photogenerating material in abinder) over an undercoating layer and/or a blocking layer, and a chargetransport layer (including a charge transport material in a binder).Additional layers, such as one or more overcoat layer or layers, may beincluded as well.

In view of such a background, improvement in electrophotographicproperties and durability, miniaturization, reduction in cost, etc., inelectrophotographic photoreceptors have been studied, andelectrophotographic photoreceptors using various materials have beenproposed.

For example, JP-A-63-65449 (the term “JP-A” as used herein means an“unexamined published Japanese patent application”), which isincorporated herein by reference in its entirety, discloses anelectrophotographic photoreceptor in which fine silicone particles areadded to a photosensitive layer, and also discloses that such additionof the fine silicone particles imparts lubricity to a surface of thephotoreceptor.

Further, in forming a photosensitive layer, a method has been proposedin which a charge transfer substance is dispersed in a binder polymer ora polymer precursor thereof, and then the binder polymer or the polymerprecursor thereof is cured. JP-B-5-47104 (the term “JP-B” as used hereinmeans an “examined Japanese patent publication”) and JP-B-60-22347,which are incorporated herein by reference in their entirety, discloseelectrophotographic photoreceptors using silicone materials as thebinder polymers or the polymer precursors thereof.

Furthermore, in order to improve mechanical strength of theelectrophotographic photoreceptor, a protective layer is formed on thesurface of the photosensitive layer in some cases. Often, acrosslinkable resin is used as a material for the protective layer.However, protective layers formed by crosslinkable resin act asinsulating layers, which impair the photoelectric characteristics of thephotoreceptor. For this reason, a method of dispersing a fine conductivemetal oxide powder (JP-A-57-128344) or a charge transfer substance(JP-A-4-15659) in the protective layer and a method of reacting a chargetransfer substance having a reactive functional group with athermoplastic resin to form the protective layer have been proposed.JP-A-57-128344 and JP-A-4-15659 are incorporated herein by reference intheir entirety.

However, even the above-mentioned conventional electrophotographicphotoreceptors are not necessarily sufficient in electrophotographiccharacteristics and durability, particularly when they are used incombination with a charger of the contact charging system (contactcharger) or a cleaning apparatus, such as a cleaning blade.

Further, when the photoreceptor is used in combination with the contactcharger and a toner obtained by chemical polymerization (polymerizationtoner), image quality may be deteriorated due to a surface of thephotoreceptor being stained with a discharge product produced in contactcharging or the polymerization toner remaining after a transfer step.Still further, the use of a cleaning blade to remove discharge productor remaining toner from the surface of the photoreceptor involvesfriction and abrasion between the surface of the photoreceptor and thecleaning blade, which tends to damage the surface of the photoreceptor,breaks the cleaning blade or turns up the cleaning blade.

The use of silicon-containing compounds in photoreceptor layers,including in photosensitive and protective layers, has been shown toincrease the mechanical lifetime of electrophotographic photoreceptors,under charging conditions and scorotron charging conditions. Forexample, U.S. Patent Application Publication U.S. 2004/0086794 to Yamadaet al., which is incorporated herein by reference in its entirety,discloses a photoreceptor having improved mechanical strength and stainresistance.

Photoreceptors having low wear rates, such as those described in U.S.2004/0086794, also have low refresh rates. Low wear and refresh ratesare a primary cause of image deletion errors, particularly underconditions of high humidity and high temperature. U.S. Pat. No.6,730,448 B2 to Yoshino et al., which is incorporated herein byreference in its entirety, addresses this issue in its disclosure ofphotoreceptors having some improvement in image quality, fixing ability,even in an environment of high heat and humidity.

It has been determined that, in electrophotographic photoreceptors,deletion of a developed image is the result of degradation of thetop-most surface of the electrophotographic photoreceptor. This deletionoccurs when the electrophotographic photoreceptor is exposed toenvironmental contaminants, such as those typically found around thecharging device of a xerographic engine. The image deletion increasesunder conditions of high heat and high humidity.

In typical electrophotographic photoreceptors, where the outermostsurface comprises a solid state solution of a hole-transportingarylamine compound in a polymeric binder material, image deletion occurswhen the environmental contaminants around the charging device reactwith hole-transporting arylamine compounds to form highly conductivespecies.

However, in electrophotographic photoreceptors in which the outermostlayer is a siloxane-organic hybrid material containing ahole-transporting arylamine moiety, image deletion occurs when theenvironmental contaminants around the charging device in the xerographicengine interact with the siloxane component of the siloxane-organichybrid material. A chemical reaction by which residual alkoxides of thesiloxane components hydrolyze to form highly polar silanol moietiesresults from this interaction. These highly polar silanols, which resideon the outermost surface of the electrophotographic photoreceptor andboth attract and retain environmental contaminants formed by thecharging device, which cause highly conductive zones to form on thesurface of the electrophotographic photoreceptor. In the presence ofhigh heat and/or high humidity, these highly conductive zones manifestas a deletion of the developed image.

Thus, the above-mentioned conventional electrophotographicphotoreceptors are not necessarily sufficient in electrophotographiccharacteristics and durability, particularly when used in high heatand/or high humidity environments.

Thus, there still remains a need for electrophotographic photoreceptorshaving high mechanical strength and improved electrophotographiccharacteristics and improved image deletion characteristics even underconditions of high temperature and high humidity. In particular, thereremains a need for an additive to siloxane-containing layers that willinteract with the environmental contaminants formed by the chargingdevice of the xerographic engine and prevent the contaminants frominteracting with siloxanes residues and that will also prevent ordecrease the deletion of developed images.

SUMMARY

Silicon-containing layers for electrophotographic photoreceptors, inwhich the silicon-containing layers have high mechanical strength,improved electrophotographic characteristics and improved image deletioncharacteristics even under conditions of high temperature and highhumidity are provided.

A method for the preparation of a silicon-containing arylamine compoundin which the arylamine compound is a derivative of 4-aminobiphenyl isseparably provided. Specifically, a method for the preparation of asilicon-containing arylamine derivative of 4-aminobiphenyl is provided,in which the silicon-containing arylamine derivative of 4-aminobiphenylis where a dicarboxylic acid salt of an alkali earth compound, preparedin an anhydrous environment.

The dicarboxylic acid salt of an alkali earth compound is further usefulas an intermediate, which can be reacted with an alkylhalide compoundcontaining a siloxane moiety to produce a siloxane containing arylaminecompound which is useful in the preparation of siloxane containingcharge transporting layers for electrophotographic application.

These and other features and advantages of various exemplary embodimentsof materials, devices, systems and/or methods according to thisinvention are described in, or are apparent from, the following detaileddescription of the various exemplary embodiments of the methods andsystems according to this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional view showing an embodiment of anelectrophotographic photoreceptor.

FIG. 2 is a schematic view showing an embodiment of an image formingapparatus.

FIG. 3 is a schematic view showing another embodiment of an imageforming apparatus.

FIG. 4 sets forth exemplary siloxane-containing arylamine compounds.

FIG. 5 sets forth a conventional process for the production ofsiloxane-containing arylamine compounds.

FIG. 6 sets forth a conventional process for the production ofsiloxane-containing arylamine compounds, including the formation of analkali earth salt intermediate.

FIG. 7 sets forth typical by-products of the conventional process ofFIG. 6.

FIG. 8 sets forth a process for the production of a dicarboxylic acidpotassium salt of an arylamine compound according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Preferred embodiments will be described in detail below with referenceto drawings in some cases. In the drawings, the same reference numeralsand signs are used to designate the same or corresponding parts, andrepeated descriptions are avoided.

Electrophotographic Photoreceptor

In electrophotographic photoreceptors of embodiments, photosensitivelayers may comprise one or more silicon-containing layers, and thesilicon-containing layers may further contain resin.

In embodiments, the resin may be a resin soluble in a liquid componentin a coating solution used for formation of this layer. Such aliquid-soluble resin may be selected based upon the liquid componentemployed. For example, if the coating solution contains an alcoholicsolvent (such as methanol, ethanol or butanol), a polyvinyl acetal resinsuch as a polyvinyl butyral resin, a polyvinyl formal resin or apartially acetalized polyvinyl acetal resin in which butyral ispartially modified with formal or acetoacetal, a polyamide resin, acellulose resin such as ethyl cellulose and a phenol resin may besuitably chosen as the alcohol-soluble resins. These resins may be usedeither alone or as a combination of two or more of them. Of theabove-mentioned resins, the polyvinyl acetal resin is used in someembodiments to obtain the benefits of its electric characteristics.

In embodiments, the weight-average molecular weight of the resin solublein the liquid component may be from 2,000 to 1,000,000, and from 5,000to 50,000. When the average molecular weight is less than 2,000, theeffect of enhancing discharge gas resistance, mechanical strength,scratch resistance, particle dispersibility, etc., tends to becomeinsufficient. However, when the average molecular weight exceeds1,000,000, the resin solubility in the coating solution decreases, andthe amount of resin added to the coating solution may be limited andpoor film formation in the production of the photosensitive layer mayresult.

Further, the amount of resin soluble in the liquid component may be, inembodiments, from 0.1 to 15% by weight, or from 0.5 to 10% by weight,based on the total amount of the coating solution. When the amount addedis less than 0.1% by weight, the effect of enhancing discharge gasresistance, mechanical strength, scratch resistance, particledispersibility, etc., tends to become insufficient. However, if theamount of the resin soluble in the liquid component exceeds 15% byweight, there is a tendency for formation of indistinct images when theelectrophotographic photoreceptor of embodiments is used at hightemperature and high humidity.

As used herein, a “high temperature environment” or “high temperatureconditions” refer to an atmosphere in which the temperature is at least28° C. A “high humidity environment” or “high humidity conditions” referto an atmosphere in which the relative humidity is at least 75%.

Silicon-containing compounds used in embodiments, contain at least onesilicon atom, but are not particularly limited. However, a compoundhaving two or more silicon atoms in its molecule may be used inembodiments. The use of the compound having two or more silicon atoms inits molecule allows both the strength and image quality of theelectrophotographic photoreceptor to be achieved at higher levels.

In embodiments, at least one member selected from silicon-containingcompounds represented by the following general formulas (1) to (3) andhydrolysates or hydrolytic condensates thereof may be used.W¹(—SiR_(3-a)Q_(a))₂   (2)W²(-D-SiR_(3-a)Q_(a))_(b)   (3)SiR_(4-c)Q_(c)   (4)

In general formulas (2) to (4), W¹ represents a divalent organic group,W² represents an organic group derived from a compound having holetransport capability, R represents a member selected from the groupconsisting of a hydrogen atom, an alkyl group and a substituted orunsubstituted aryl group, Q represents a hydrolytic group, D representsa divalent group, a represents an integer of 1 to 3, b represents aninteger of 2 to 4, and c represents an integer of 1 to 4.

R in general formulas (2) to (4) represents a hydrogen atom, an alkylgroup (preferably an alkyl group having 1 to 5 carbon atoms) or asubstituted or unsubstituted aryl group (preferably a substituted orunsubstituted aryl group having 6 to 15 carbon atoms), as describedabove.

Further, the hydrolytic group represented by Q in general formulas (2)to (4) means a functional group which can form a siloxane bond (O—Si—O)by hydrolysis in the curing reaction of the compound represented by anyone of general formulas (2) to (4). Non-limiting examples of thehydrolytic groups that may be used in embodiments include a hydroxylgroup, an alkoxyl group, a methyl ethyl ketoxime group, a diethylaminogroup, an acetoxy group, a propenoxy group and a chloro group. Inparticular embodiments, a group represented by —OR″ (R″ represents analkyl group having 1 to 15 carbon atoms or a trimethylsilyl group) maybe used.

In general formula (3), the divalent group represented by D may be, inembodiments, a divalent hydrocarbon group represented by —C_(n)H_(2n)—,—C_(n)H_(2n-2)—, —C_(n)H_(2n-4)— (n is an integer of 1 to about 15, andpreferably from 2 to about 10), —CH₂—C₆H₄— or —C₆H₄—C₆H₄—, anoxycarbonyl group (—COO—), a thio group (—S—), an oxy group (—O—), anisocyano group (—N═CH—) or a divalent group in which two or more of themare combined. The divalent group may have a substituent group such as analkyl group, a phenyl group, an alkoxyl group or an amino group on itsside chain. When D is the above-mentioned preferred divalent group,proper flexibility may be imparted to an organic silicate skeleton,thereby tending to improve the strength of the layer.

Non-limiting examples of the compounds represented by theabove-mentioned general formula (2) are shown in Table 1. TABLE 1 No.Structural Formula III-1 (MeO)₃Si—(CH₂)₂—Si(OMe)₃ III-2(MeO)₂Me—(CH2)₂—SiMe(OMe)₂ III-3 (MeO)₂MeSi—(CH₂)₆—SiMe(OMe)₂ III-4(MeO)₃Si—(CH₂)₆—Si(OMe)₃ III-5 (EtO)₃Si—(CH₂)₆—Si(OEt)₃ III-6(MeO)₂MeSi—(CH₂)₁₀—SiMe(OMe)₂ III-7 (MeO)₃Si—(CH₂)₃—NH—(CH₂)₃—Si(OMe)₃III-8 (MeO)₃Si—(CH₂)₃—NH—(CH₂)₂—NH—(CH₂)₃—Si(OMe)₃ III-9

III-10

III-11

III-12

III-13

III-14

III-15 (MeO)₃SiC₃H₆—O—CH₂CH{—O—C₃H₆Si(OMe)₃}—CH₂{—O—C₃H₆Si(OMe)₃} III-16(MeO)₃SiC₂H₄—SiMe₂—O—SiMe₂—O—SiMe₂—C₂H₄Si(OMe)₃

Further, in the above-mentioned general formula (3), there is noparticular limitation on the organic group represented by W², as long asit is a group having hole transport capability. However, in particularembodiments, W² may be an organic group represented by the followinggeneral formula (6):

wherein Ar¹, Ar², Ar³ and Ar⁴, which may be the same or different, eachrepresents a substituted or unsubstituted aryl group, Ar⁵ represents asubstituted or unsubstituted aryl or arylene group, k represents 0 or 1,and at least one of Ar¹ to Ar⁵ has a bonding hand to connect with-D-SiR_(3-a)Q_(a) in general formula (3).

Ar¹ to Ar⁴ in the above-mentioned general formula (6) are eachpreferably any one of the following formulas (7) to (13):

In formulas (7) to (13), R⁶ represents a member selected from the groupconsisting of a hydrogen atom, an alkyl group having 1 to 4 carbonatoms, an unsubstituted phenyl group or a phenyl group substituted by analkyl group having 1 to 4 carbon atoms or an alkoxyl group having 1 to 4carbon atoms, and an aralkyl group having 7 to 10 carbon atoms; R⁷ to R⁹each represents a member selected from the group consisting of ahydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxylgroup having 1 to 4 carbon atoms, an unsubstituted phenyl group or aphenyl group substituted by an alkoxyl group having 1 to 4 carbon atoms,an aralkyl group having 7 to 10 carbon atoms, and a halogen atom; Arrepresents a substituted or unsubstituted arylene group; X represents-D-SiR_(3-a)Q_(a) in general formula (3); m and s each represents 0 or1; q and r each represents an integer of 1 to 10; and t and t′ eachrepresents an integer of 1 to 3.

Here, Ar in formula (7) may be one represented by the following formula(14) or (15):

In formulas (14) and (15), R¹⁰ and R¹¹ each represent a member selectedfrom the group consisting of a hydrogen atom, an alkyl group having 1 to4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, anunsubstituted phenyl group or a phenyl group substituted by an alkoxylgroup having 1 to 4 carbon atoms, an aralkyl group having 7 to 10 carbonatoms, and a halogen atom; and t represents an integer of 1 to 3.

Further, Z′ in formula (13) is preferably one represented by any one ofthe following formulas (16) to (23):—(CH₂)_(q)—  (16)—(CH₂CH₂O)_(r)—  (17)

In formulas (16) to (23), R¹² and R¹³ each represent a member selectedfrom the group consisting of a hydrogen atom, an alkyl group having 1 to4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, anunsubstituted phenyl group or a phenyl group substituted by an alkoxylgroup having 1 to 4 carbon atoms, an aralkyl group having 7 to 10 carbonatoms, and a halogen atom; W represents a divalent group; q and r eachrepresents an integer of 1 to 10; and t represents an integer of 1 to 3.

W in the above-mentioned formulas (22) and (23) may be any one ofdivalent groups represented by the following formulas (24) to (32):—CH₂—  (24)—C(CH₃)₂—  (25)—O—  (26)—S—  (27)—C(CF₃)₂—  (28)—Si(CH₃)₂—  (29)

In formula (31), u represents an integer of 0 to 3.

Further, in general formula (6), Ar⁵ is the aryl group illustrated inthe description of Ar¹ to Ar⁴, when k is 0, and an arylene groupobtained by removing a certain hydrogen atom from such an aryl group,when k is 1.

Combinations of Ar¹, Ar², Ar³, Ar⁴, Ar⁵ and integer k in formula (6) anda group represented by -D-SiR_(3-a)Q_(a) in general formula (3) inparticular exemplary embodiments are shown in FIG. 4; additionalexemplary embodiments can be found in U.S. 2004/0086794, U.S. Pat. No.6,730,448 B2 and in U.S. patent application Ser. No. 10/998,585,entitled “Silicon-Containing Layers for ElectrophotographicPhotoreceptors and Methods for Making the Same,” the entire disclosuresof which are incorporated herein by reference. In FIG. 4, S represents-D-SiR_(3-a)Q_(a) linked to Ar¹ to Ar⁵, Me represents a methyl group, Etrepresents an ethyl group, and Pr represents a propyl group.

Further, in embodiments, the silicon compounds represented by theabove-mentioned general formula (4) may include silane coupling agentssuch as a monofunctional alkoxysilane (c=1) such astrimethylmethoxysilane; a bifunctional alkoxysilane (c=2) such asdimethyldimethoxysilane, diphenyldimethoxysilane ormethylphenyldimethoxysilane; a trifunctional alkoxysilane (c=3) such asmethyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane,methyltrimethoxyethoxysilane, vinyltrimethoxysilane,vinyltriethoxysilane, phenyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane,γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane,γ-aminopropylmethyldimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltriethoxysilane,(tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane,(3,3,3-trifluoropropyl)trimethoxysilane,3-(heptafluoroisopropoxy)propyltriethoxysilane, 1H,1H,2H,2H-perfluoroalkyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane or1H,1H,2H,2H-perfluorooctyltriethoxysilane; and a tetrafunctionalalkoxysilane (c=4) such as tetramethoxysilane or tetraethoxysilane.

In order to improve the strength of the photosensitive layer, thetrifunctional alkoxysilanes and the tetrafunctional alkoxysilanes may beused in embodiments, and in order to improve the flexibility and filmforming properties, the monofunctional alkoxysilanes and thebifunctional alkoxysilanes may be used in embodiments.

Silicone hard coating agents containing these coupling agents can alsobe used in embodiments. Commercially available hard coating agentsinclude KP-85, X-40-9740 and X-40-2239 (available from Shinetsu SiliconeCo., Ltd.), and AY42-440, AY42-441 and AY49-208 (available from TorayDow Corning Co., Ltd.).

In embodiments, the silicon-containing layer may contain either only oneof the silicon-containing compounds represented by the above-mentionedgeneral formulas (2) to (4) or two or more of them. Further, thecompounds represented by general formulas (2) to (4) may include amonofunctional compound (a compound in which a or c is 1), abifunctional compound (a compound in which a or c is 2), a trifunctionalcompound (a compound in which a or c is 3) and/or a tetrafunctionalcompound (a compound in which a or c is 4). However, in particularembodiments, the number of silicon atoms derived from thesilicon-containing compounds represented by the above-mentioned generalformulas (2) to (4) in the silicon-containing layer satisfies thefollowing equation (26):(N_(a=3)+N_(c≧3))/N_(total)≦0.5   (26)

wherein N_(a=3) represents the number of silicon atoms derived from—SiR_(3-a)Q_(a) of the silicon-containing compound represented bygeneral formula (2) or (3), in which a is 3; N_(c≧3) represents thenumber of silicon atoms derived from the silicon-containing compoundrepresented by general formula (4) in which c is 3 or 4, and N_(total)represents the total of the number of silicon atoms derived from—SiR_(3-a)Q_(a) of the silicon compound represented by general formula(2) or (3) and the number of silicon atoms derived from thesilicon-containing compound represented by general formula (4). That isto say, the ratio of silicon-containing compounds contained is set sothat the number of silicon atoms derived from the trifunctional compoundor the tetrafunctional compound becomes 0.5 or less based on the numberof silicon atoms derived from the silicon-containing compoundsrepresented by general formulas (2) to (4) (in the case of the compoundrepresented by general formula (2) or (3), the silicon atoms are limitedto ones derived from —SiR_(3-a)Q_(a), and the same applies hereinafter).When the value of the left side of equation (26) exceeds 0.5, anindistinct image tends to be liable to occur at high temperature andhigh humidity. When the value of the left side of equation (26) isdecreased, a decrease in strength may also result. However, the use of asilicon-containing compound having two or more silicon atoms in itsmolecule can improve the strength.

In order to further improve the stain adhesion resistance and lubricityof embodiments of the electrophotographic photoreceptor, various fineparticles can also be added to the silicon-containing layer.Non-limiting examples of the fine particles include fine particlescontaining silicon, such as fine particles containing silicon as aconstituent element, and specifically include colloidal silica and finesilicone particles. Fine particles may be used either alone or as acombination of two or more of such fine particles.

Colloidal silica used in embodiments as the fine particles containingsilicon may be selected from acidic or alkaline aqueous dispersions offine particles having an average particle size of 1 to 100 nm, or 10 to30 nm, and dispersions of fine particles in organic solvents, such as analcohol, a ketone or an ester. In general, commercially availableparticles may be used. There is no particular limitation on the solidcontent of colloidal silica in a top surface layer of theelectrophotographic photoreceptor of embodiments. However, inembodiments, colloidal silica is used within the range of 1 to 50% byweight, or 5 to 30% by weight, based on the total solid content of thetop surface layer, in terms of film-forming properties, electriccharacteristics and strength.

Fine silicone particles that may be used as fine particles containingsilicon in embodiments may be selected from silicone resin particles,silicone rubber particles and silica particles surface-treated withsilicone. Such particles may be spherical and may have an averageparticle size of 1 to 500 nm or 10 to 100 nm. In general, commerciallyavailable particles may be used in embodiments.

In embodiments, the fine silicone particles are small-sized particlesthat are chemically inactive and excellent in dispersibility in a resin,and further are low in content as may be necessary for obtainingsufficient characteristics. Accordingly, the surface properties of theelectrophotographic photoreceptor can be improved without inhibition ofthe crosslinking reaction. That is to say, fine silicone particlesimprove the lubricity and water repellency of surfaces ofelectrophotographic photoreceptors where incorporated into strongcrosslinked structures, which may then be able to maintain good wearresistance and stain adhesion resistance for a long period of time. Thecontent of the fine silicone particles in the silicon-containing layerof embodiments may be within the range of 0.1 to 20% by weight, orwithin the range of 0.5 to 10% by weight, based on the total solidcontent of the silicon-containing layer.

Other fine particles that may be used in embodiments include finefluorine-based particles, such as ethylene tetrafluoride, ethylenetrifluoride, propylene hexafluoride, vinyl fluoride and vinylidenefluoride, and semiconductive metal oxides such as ZnO—Al₂O₃, SnO₂—Sb₂O₃,In₂O₃—SnO₂, ZnO—TiO₂, MgO—Al₂O₃, FeO—TiO₂, TiO₂, SnO₂, In₂O₃, ZnO andMgO.

In conventional electrophotographic photoreceptors, when theabove-mentioned fine particles are contained in the photosensitivelayer, the compatibility of the fine particles with a charge transfersubstance or a binding resin may become insufficient, which causes layerseparation in the photosensitive layer, and thus forms an opaque film.As a result, the electric characteristics have deteriorated in somecases. In contrast, the silicon compound-containing layer of embodiments(a charge transfer layer in this case) may contain the resin soluble inthe liquid component in the coating solution used for formation of thislayer and the silicon compound, thereby improving the dispersibility ofthe fine particles in the silicon compound-containing layer.Accordingly, the pot life of the coating solution can be sufficientlyprolonged, and it becomes possible to prevent deterioration of theelectric characteristics.

Further, an additive such as a plasticizer, a surface modifier, anantioxidant, or an agent for preventing deterioration by light can alsobe used in the silicon compound-containing layer of embodiments.Non-limiting examples of plasticizers that may be used in embodimentsinclude, for example, biphenyl, biphenyl chloride, terphenyl, dibutylphthalate, diethylene glycol phthalate, dioctyl phthalate,triphenylphosphoric acid, methylnaphthalene, benzophenone, chlorinatedparaffin, polypropylene, polystyrene and various fluorohydrocarbons.

The antioxidants may include an antioxidant having a hindered phenol,hindered amine, thioether or phosphite partial structure. This iseffective for improvement of potential stability and image quality inenvironmental variation. The antioxidants include an antioxidant havinga hindered phenol, hindered amine, thioether or phosphite partialstructure. This is effective for improvement of potential stability andimage quality in environmental variation. For example, the hinderedphenol antioxidants include SUMILIZER BHT-R, SUMILIZER MDP-S, SUMILIZERBBM-S, SUMILIZER WX-R, SUMILIZER NW, SUMILIZER BP-76, SUMILIZER BP-101,SUMILIZER GA-80, SUMILIZER GM and SUMILIZER GS (the above aremanufactured by Sumitomo Chemical Co., Ltd.), IRGANOX 1010, IRGANOX1035, IRGANOX 1076, IRGANOX 1098, IRGANOX 1135, IRGANOX 1141, IRGANOX1222, IRGANOX 1330, IRGANOX 1425WLj, IRGANOX 1520Lj, IRGANOX 245,IRGANOX 259, IRGANOX 3114, IRGANOX 3790, IRGANOX 5057 and IRGANOX 565(the above are manufactured by Ciba Specialty Chemicals), and ADECASTABAO-20, ADECASTAB AO-30, ADECASTAB AO-40, ADECASTAB AO-50, ADECASTABAO-60, ADECASTAB AO-70, ADECASTAB AO-80 and ADECASTAB AO-330i (the aboveare manufactured by Asahi Denka Co., Ltd.). The hindered amineantioxidants include SANOL LS2626, SANOL LS765, SANOL LS770, SANOLLS744, TINUVIN 144, TINUVIN 622LD, MARK LA57, MARK LA67, MARK LA62, MARKLA68, MARK LA63 and SUMILIZER TPS, and the phosphite antioxidantsinclude MARK 2112, MARK PEP•8, MARK PEP•24G, MARK PEP•36, MARK 329K andMARK HP•10. Of these, the hindered phenol and hindered amineantioxidants are particularly preferred.

A siloxane-containing antioxidant may also incorporated into thesilicon-containing layer of embodiments. In certain embodiments, thesiloxane-containing antioxidant may be wholly or at least partiallylocated in the siloxane region of the silicon-containing layer. Thesiloxane-containing antioxidants may include any siloxane-containingantioxidant having a hindered phenol, hindered amine, thioether orphosphite partial structure. Use of siloxane-containing antioxidantshaving a hindered phenol, hindered amine, thioether or phosphite partialstructure, as described herein, has been found to drastically improveimage deletion error even in long term cycling under conditions of highhumidity and high temperature. Suitable siloxane-containing antioxidantsthat may be used in accordance with embodiments can be found in U.S.patent application Ser. No. 10/998,585.

There is no particular limitation on the thickness of thesilicon-containing layer, however, in embodiments, thesilicon-containing layer may be in the range from about 2 to about 5 μmin thickness, preferably from about 2.7 to about 3.2 μm in thickness.

In embodiments of the invention, the photosensitive layer may comprisethe silicon compound-containing layer as described above. Inembodiments, the photosensitive has a peak area in the region of −40 to0 ppm (S₁) and a peak area in the region of −100 to −50 ppm (S₂) in a²⁹Si-NMR spectrum that satisfy the following equation (1):S₁/(S₁+S₂)≧0.5   (1)When S₁/(S₁+S₂) is less than 0.5, defects are liable to occur. Inparticular, there is a tendency to cause an indistinct image at hightemperature and the pot life shortened. Thus, S₁/(S₁+S₂) may be about0.6 or more, preferably about 0.7 or more.

The ²⁹Si-NMR spectrum of the photosensitive layer can be measuredthrough the following procedure. First, the photosensitive layer isseparated from the electrophotographic photoreceptor by use of asilicon-free adhesive tape, and a sample tube (7 mm in diameter) made ofzirconia is filled with 150 mg of the resulting separated product. Thesample tube is set on a ²⁹Si-NMR spectral measuring apparatus (forexample, UNITY-300 manufactured by Varian, Inc.), and measurements aremade under the following conditions:

-   -   Frequency: 59.59 MHz;    -   Delay time: 10.00 seconds;    -   Contact time: 2.5 milliseconds;    -   Measuring temperature: 25° C.;    -   Integrating number: 10,000 times; and    -   Revolution: 4,000±500 rpm.

The electrophotographic photoreceptor of embodiments may be either afunction-separation-type photoreceptor, in which a layer containing acharge generation substance (charge generation layer) and a layercontaining a charge transfer substance (charge transfer layer) areseparately provided, or a monolayer-type photoreceptor, in which boththe charge generation layer and the charge transfer layer are containedin the same layer, as long as the electrophotographic photoreceptor ofthe particular embodiment has the photosensitive layer provided with theabove-mentioned silicon compound-containing layer. Theelectrophotographic photoreceptor of the invention will be described ingreater detail below, taking the function-separation-type photoreceptoras an example.

FIG. 1 is a cross-sectional view schematically showing an embodiment ofthe electrophotographic photoreceptor of the invention. Theelectrophotographic photoreceptor 1 shown in FIG. 1 is afunction-separation-type photoreceptor in which a charge generationlayer 13 and a charge transfer layer 14 are separately provided. Thatis, an underlayer 12, the charge generation layer 13, the chargetransfer layer 14 and a protective layer 15 are laminated onto aconductive support 11 to form a photosensitive layer 16. The protectivelayer 15 contains a resin soluble in the liquid component contained inthe coating solution used for formation of this layer and the siliconcompound. Further, a peak area in the region of −40 to 0 ppm and a peakarea in the region of −100 to −50 ppm in a 29Si-NMR spectrum of thephotosensitive layer 16 satisfy equation (1).

The conductive support 11 may include, for example, a metal plate, ametal drum or a metal belt using a metal such as aluminum, copper, zinc,stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold ora platinum, or an alloy thereof; and paper or a plastic film or beltcoated, deposited or laminated with a conductive polymer, a conductivecompound such as indium oxide, a metal such as aluminum, palladium orgold, or an alloy thereof. Further, surface treatment (such as anodicoxidation coating, hot water oxidation, chemical treatment, or coloring)or diffused reflection treatment (such as graining) can also be appliedto a surface of the support 11.

Binding resins used in the underlayer 12 of embodiments may include butare not limited to, one or more polyamide resins, vinyl chloride resins,vinyl acetate resins, phenol resins, polyurethane resins, melamineresins, benzoguanamine resins, a polyimide resins, polyethylene resins,polypropylene resins, polycarbonate resins, acrylic resins, methacrylicresins, vinylidene chloride resins, polyvinyl acetal resins, vinylchloride-vinyl acetate copolymers, polyvinyl alcohol resins, awater-soluble polyester resins, nitrocelluloses, caseins, gelatins,polyglutamic acids, starches, starch acetates, amino starches,polyacrylic acids, polyacrylamides, zirconium chelate compounds, titanylchelate compounds, titanyl alkoxide compounds, organic titanylcompounds, silane coupling agents and mixtures thereof. Further, fineparticles of titanium oxide, aluminum oxide, silicon oxide, zirconiumoxide, barium titanate, a silicone resin or the like may be added to theabove-mentioned binding resin in embodiments.

As a coating method in forming the underlayer of embodiments, anordinary method such as blade coating, Mayer bar coating, spray coating,dip coating, bead coating, air knife coating or curtain coating may beemployed. The thickness of the underlayer may be from about 0.01 toabout 40 μm.

Non-limiting examples of charge generation substances that may becontained in the charge generation layer 13 of embodiments include, butare not limited to, various organic pigments and organic dyes; such asazo pigments, quinoline pigments, perylene pigments, indigo pigments,thioindigo pigments, bisbenzimidazole pigments, phthalocyanine pigments,quinacridone pigments, quinoline pigments, lake pigments, azo lakepigments, anthraquinone pigments, oxazine pigments, dioxazine pigments,triphenylmethane pigments, azulenium dyes, squalium dyes, pyrylium dyes,triallylmethane dyes, xanthene dyes, thiazine dyes and cyanine dyes; andinorganic materials such as amorphous silicon, amorphous selenium,tellurium, selenium-tellurium alloys, cadmium sulfide, antimony sulfide,zinc oxide and zinc sulfide. In embodiments, cyclocondensed aromaticpigments, perylene pigments and azo pigments may be used to impartsensitivity, electric stability and photochemical stability againstirradiated light. These charge generation substances may be used eitheralone or as a combination of two or more.

In embodiments, the charge generation layer 13 may be formed by vacuumdeposition of the charge generation substance or application of acoating solution in which the charge generation substance is dispersedin an organic solvent containing a binding resin. The binding resinsused in the charge generation layer of embodiments include polyvinylacetal resins such as polyvinyl butyral resins, polyvinyl formal resinsor partially acetalized polyvinyl acetal resins in which butyral ispartially modified with formal or acetoacetal, polyamide resins,polyester resins, modified ether type polyester resins, polycarbonateresins, acrylic resins, polyvinyl chloride resins, polyvinylidenechlorides, polystyrene resins, polyvinyl acetate resins, vinylchloride-vinyl acetate copolymers, silicone resins, phenol resins,phenoxy resins, melamine resins, benzoguanamine resins, urea resins,polyurethane resins, poly-N-vinylcarbazole resins, polyvinylanthraceneresins, polyvinylpyrene resins and mixtures thereof. In embodiments inwhich one or more of polyvinyl acetal resins, vinyl chloride-vinylacetate copolymers, phenoxy resins or modified ether type polyesterresins are used, the dispersibility of the charge generation substancemay be improved to cause no occurrence of coagulation of the chargegeneration substance, and a coating solution that is stable for a longperiod of time may be obtained. The use of such a coating solution inembodiments makes it possible to form a uniform coating easily andsurely. As a result, the electric characteristics may be improved, andimage defects may be prevented. Further, the compounding ratio of thecharge generation substance to the binding resin may be, in embodiments,within the range of from about 5:1 to about 1:2 by volume ratio.

Further, the solvents used in preparing the coating solution inembodiments may include organic solvents such as methanol, ethanol,n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethylcellosolve, acetone, methyl ethyl ketone, cyclohexanone, chlorobenzene,methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylenechloride, chloroform and mixtures thereof.

Methods for applying the coating solution in embodiments include thecoating methods described above with reference to the underlayer. Thethickness of the charge generation layer 13 thus formed may be fromabout 0.01 to about 5 μm, preferably from about 0.1 to about 2 μm. Whenthe thickness of the charge generation layer 13 is less than 0.01 μm, itbecomes difficult to uniformly form the charge generation layer. On theother hand, when the thickness exceeds 5 μm, the electrophotographiccharacteristics tend to significantly deteriorate.

Further, a stabilizer such as an antioxidant or an inactivating agentcan also be added to the charge generation layer 13 in embodiments.Non-limiting examples of antioxidants that may be used include but arenot limited to antioxidants such as phenolic, sulfur, phosphorus andamine compounds. Inactivating agents that may be used in embodiments mayinclude bis(dithiobenzyl)nickel and nickel di-n-butylthiocarbamate.

In embodiments, the charge transfer layer 14 can be formed by applying acoating solution containing the charge transfer substance and a bindingresin, and further fine particles, an additive, etc., as describedabove.

Low molecular weight charge transfer substances that may be used inembodiments may include, for example, pyrene, carbazole, hydrazone,oxazole, oxadiazole, pyrazoline, arylamine, arylmethane, benzidine,thiazole, stilbene and butadiene compounds. In embodiments, highmolecular weight charge transfer substances may be used and include, forexample, poly-N-vinylcarbazoles, poly-N-vinylcarbazole halides,polyvinyl pyrenes, polyvinylanthracenes, polyvinylacridines,pyrene-formaldehyde resins, ethylcarbazole-formaldehyde resins,triphenylmethane polymers and polysilanes. Triphenylamine compounds,triphenylmethane compounds and benzidine compounds may be used inembodiments to promote mobility, stability and transparency to light.Further, silicon compound represented by general formula (3) can also beused as charge transfer substances in particular embodiments.

As binding resins in embodiments, high molecular weight polymers thatcan form an electrical insulating film may be used. For example, whenpolyvinyl acetal resins, polyamide resins, cellulose resins, phenolresins, etc., which are soluble in alcoholic solvents, are used, bindingresins used together with these resins include polycarbonates,polyesters, methacrylic resins, acrylic resins, polyvinyl chlorides,polyvinylidene chlorides, polystyrenes, polyvinyl acetates,styrene-butadiene copolymers, vinylidene chloride-acrylonitrilecopolymers, vinyl chloride-vinyl acetate copolymers, vinylchloride-vinyl acetate-maleic anhydride copolymers, silicone resins,silicone-alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins,poly-N-vinylcarbazoles, polyvinyl butyrals, polyvinyl formals,polysulfones, casein, gelatin, polyvinyl alcohols, phenol resins,polyamides, carboxymethyl celluloses, vinylidene chloride-based polymerlatexes and polyurethanes. Of the above-mentioned high molecular weightpolymers, polycarbonates, polyesters, methacrylic resins and acrylicresins have excellent compatibility with the charge transfer substance,solubility and strength.

The charge transfer layer 14 of embodiments may further contain anadditive such as a plasticizer, a surface modifier, an antioxidant or anagent for preventing deterioration by light.

The thickness of the charge transfer layer 14 may be, in embodiments,from about 5 to about 50 μm, preferably from about 10 to about 40 μm.When the thickness of the charge transfer layer is less than 5 μm,charging becomes difficult. However, thicknesses exceeding 50 μm resultsignificant deterioration of the electrophotographic characteristics.

Protective layer 15 may contain, in embodiments, resins soluble inliquid components in coating solution used for formation of protectivelayers and silicon compounds as described above. Protective layer 15 mayfurther contain a lubricant or fine particles of a silicone oil or afluorine material, which can also improve lubricity and strength.Non-limiting examples of the lubricants include the above-mentionedfluorine-based silane coupling agents. Fine particles to be dispersed inthe protective layer 15 of embodiments may include fine particlescomprising resins obtained by copolymerizing fluororesins with hydroxylgroup-containing monomers, as described in Proceedings of Lectures inthe Eighth Polymer Material Forum, page 89, and semiconductive metaloxides, as well as the above-mentioned fine silicone particles and finefluorine-based particles. The thickness of the protective layer may be,in embodiments, from about 0.1 to about 10 μm, preferably from about 0.5to about 7 μm.

The electrophotographic photoreceptor of embodiments should not beconstrued as being limited to the abovementioned constitution. Forexample, the electrophotographic photoreceptor shown in FIG. 1 isprovided with the protective layer 15. However, when the charge transferlayer 14 contains the resin soluble in the liquid component in thecoating solution used for formation of this layer and the siliconcompound, the charge transfer layer 14 may be used as a top surfacelayer (a layer on the side farthest apart from the support 11) withoutusing the protective layer 15. In this case, the charge transfersubstance contained in the charge transfer layer 14 is preferablysoluble in the liquid component in the coating solution used forformation of the charge transfer layer 14. For example, when the coatingsolution used for formation of the charge transfer layer 14 contains thealcoholic solvent, the silicon compounds represented by theabove-mentioned general formula (3) and compounds represented by thefollowing formulas (VI-1) to (VI-16) are preferably used as the chargetransfer substances.

Other exemplary charge transport molecules include, but are not limitedto, the various compounds identified above as the organic group W²,which have hole transport capability. In embodiments, a particularlypreferred charge transport molecule is the arylamine of formula (33):

Production of such arylamine charge transport compounds, however, isgenerally a costly, time-consuming, multi-step process.

The conventional process for producing an exemplary arylamine chargetransport compound, such as the compound of formula (33), is a complexeleven step synthesis, the pertinent portions of which are depicted inFIG. 5. The synthesis is made difficult by the fact that the arylaminecharge transport compounds are generally hydrolytically sensitive.Further difficulties arise because these compounds are highly viscoussyrups which must be purified by column chromatography.

In particular, difficulties arise in the condensation of dicarboxylicacids with silicon-containing compounds to generate the final arylaminecharge transport compounds. FIG. 6 shows an exemplary reaction underthis procedure.

In the procedure shown in FIG. 6, a dibasic hole-transporting acid,Compound D, is suspended in a toluene-DMF reaction solvent and heatedwith an excess of potassium carbonate to generate the potassium salt,Compound E. After several hours, the reaction temperature is slowlyraised to 150° C. to azeotropically remove water generated during thereaction and to distill off toluene. The mixture is then cooled.

A silicon-containing compound, such as 3-halopropylsilane esters, forexample 3-iodopropyldiisopropoxymethylsilane, is added in excess, alongwith a small amount of isopropanol. The condensation reaction is allowedto proceed at 90° for 5 hours. A crude product, Compound C, is obtainedby toluene extraction and brine washing. Compound C has an highperformance liquid chromatography purity of approximately 95% and, anoligomer content of from 5-10%, as determined by gas phasechromatography analysis. The oligomer content is attributable tohydrolysis and polymerization due to residual traces of water in thecondensation reaction mixture.

Because this material is not sufficiently pure to use directly, it mustbe purified by column chromatography. In the best case, a 70% yield offinal product is recovered.

There are deficiencies related to this reaction scheme. For example, arelatively high oligomer content is observed, even when attempts aremade to make the condensation reaction components anhydrous.

In addition, the use of isopropanol results in a number of impurities,such as those shown in FIG. 7. Impurities (1) and (2) arise frombase-catalyzed transesterification reactions by isopropanol on the finalproduct and have been identified in mass spectroscopy/liquidchromatography spectra of crude reaction mixtures. Impurity (3) isformed by a base catalyzed SN₂ reaction by isopropanol on thesilicon-containing compound and can be isolated by high vacuumdistillation of the crude reaction mixture.

A process for producing arylamine charge transport compound is to reactdicarboxylic acids with isolated anhydrous alkali earth salts to formanhydrous alkali earth salts of the dicarboxylic acids. These anhydrousalkali earth salts of dicarboxylic acids are then reacted withsilicon-containing compounds to generate the final arylamine chargetransport compounds. This process has numerous advantages over theconventional process set forth above: (1) it eliminates added base, (2)it eliminates added isopropanol, (3) it eliminates the need toazeotropically remove water produced during salt formation and theextensive heating necessary to azeotropically remove water and (4)yields and quality are not compromised.

An alkali earth salt of a dicarboxylic acid derivative of an arylaminecan be conveniently prepared in the following manner and as shown inFIG. 8.

The dicarboxylic acid derivative of an arylamine, Compound D, issuspended in a solvent and slowly added two equivalents of an alkaliearth alkyl oxide, such as potassium isopropoxide. Suitable solventsinclude DMF, methanol, ethanol, propanols, butanols, pentanols, hexanolsand mixtures thereof, with DMF and isopropanol being preferred. Suitablealkali earths include, for example, lithium, sodium, potassium,rubidium, cesium, and francium, with potassium being preferred. A whitesolid is precipitated from this mixture. The mixture is heated at atemperature just below reflux while stirring is maintained. The reactioncan be conducted over a period of time ranging from about 15 minutes toabout 5 hours, such as about 30 minutes to about 2 hours or about 1hour. The mixture is then cooled, filtered and dried in vacuo. The yieldof dicarboxylate salt is quantitative, with the only losses beingmechanical in nature. The isolated product is stable, non-hygroscopic,has an HPLC purity of 99+%, and can easily be handled and stored in airor under dry nitrogen.

The result of this process is the formation of a desired anhydrousarylamine compound, which can broadly be characterized as a derivativeof 4-aminobiphenyl. Thus, for example, the arylamine compounds providedby the present invention can be represented by the following generalformula (36):4-aminobiphenyl-(R¹—CH₂—CH₂—COO⁻X₁ ⁺)(R²—CH₂—CH₂—COO⁻X₂ ⁺)   (36)where R¹ and R², which can be the same or different, are as describedabove, and X₁ and X₂, which can be the same or different, are cationicgroups, such as hydrogen ions (H⁺), potassium ions (K⁺), or the like.

In order to obtain an exemplary arylamine charge transport compound fromthe alkaline earth dicarboxylic acid salt, stoichiometric amounts of asilicon-containing compound and Compound E are dissolved in DMF andallowed to react for approximately 30 minutes at 85° C. Suitablesilicon-containing compounds include siloxane-containing compounds, suchas 3-halopropylsilane esters, for example3-iodopropyldiisopropoxymethylsilane. These reactions are homogeneousand do not contain any added potassium carbonate. The product salt,potassium iodide, has a very high solubility in DMF. Thus, a crudeproduct, Compound C is obtained by toluene extraction and brine washing.Compound C has an high performance liquid chromatography purity ofapproximately 95% and, an oligomer content of from about 1 to about 10%,but is typically about 4%, as determined by gel permeationchromatography analysis.

After each step in the overall process, suitable separation, filtration,and purification processes can be conducted, as desired. For example,after the second step, the final product can be isolated, for example,by a suitable recrystallization procedure. All of these procedures areconventional and will be apparent to those skilled in the art. However,a benefit of the process, as described above, is that the reactionproduct mixture from the first step can be directly used in the secondstep without isolation or purification.

Image Forming Apparatus and Process Cartridge

FIG. 2 is a schematic view showing an embodiment of an image formingapparatus. In the apparatus shown in FIG. 2, the electrophotographicphotoreceptor 1 constituted as shown in FIG. 1 is supported by a support9, and rotatable at a specified rotational speed in the directionindicated by the arrow, centered on the support 9. A contact chargingdevice 2, an exposure device 3, a developing device 4, a transfer device5 and a cleaning unit 7 are arranged in this order along the rotationaldirection of the electrophotographic photoreceptor 1. Further, thisexemplary apparatus is equipped with an image fixing device 6, and amedium P to which a toner image is to be transferred is conveyed to theimage fixing device 6 through the transfer device 5.

The contact charging device 2 has a roller-shaped contact chargingmember. The contact charging member is arranged so that it comes intocontact with a surface of the photoreceptor 1, and a voltage is applied,thereby being able to give a specified potential to the surface of thephotoreceptor 1. In embodiments, a contact charging member may be formedfrom a metal such as aluminum, iron or copper, a conductive polymermaterial such as a polyacetylene, a polypyrrole or a polythiophene, or adispersion of fine particles of carbon black, copper iodide, silveriodide, zinc sulfide, silicon carbide, a metal oxide or the like in anelastomer material such as polyurethane rubber, silicone rubber,epichlorohydrin rubber, ethylene-propylene rubber, acrylic rubber,fluororubber, styrene-butadiene rubber or butadiene rubber. Non-limitingexamples of metal oxides that may be used in embodiments include ZnO,SnO₂, TiO₂, In₂O₃, MoO₃ and complex oxides thereof. Further, aperchlorate may be added to the elastomer material to impartconductivity.

Further, a covering layer can also be provided on a surface of thecontact charging member of embodiments. Non-limiting examples ofmaterials that may be used in embodiments for forming a covering layerinclude N-alkoxy-methylated nylon, cellulose resins, vinylpyridineresins, phenol resins, polyurethanes, polyvinyl butyrals, melamines andmixtures thereof. Furthermore, emulsion resin materials such as acrylicresin emulsions, polyester resin emulsions or polyurethanes, may beused. In order to further adjust resistivity, conductive agent particlesmay be dispersed in these resins, and in order to prevent deterioration,an antioxidant can also be added thereto. Further, in order to improvefilm forming properties in forming the covering layer, a leveling agentor a surfactant may be added to the emulsion resin in embodiments.

The resistance of the contact charging member of embodiments may be from10⁰ to 10¹⁴ Ωcm, and from 10² to 10¹² Ωcm. When a voltage is applied tothis contact charging member, either a DC voltage or an AC voltage canbe used as the applied voltage. Further, a superimposed voltage of a DCvoltage and an AC voltage can also be used.

In the exemplary apparatus shown in FIG. 2, the contact charging memberof the contact charging device 2 is in the shape of a roller. However,such a contact charging member may be in the shape of a blade, a belt, abrush or the like.

Further, in embodiments an optical device that can perform desiredimagewise exposure to a surface of the electrophotographic photoreceptor1 with a light source such as a semiconductor laser, an LED (lightemitting diode) or a liquid crystal shutter, may be used as the exposuredevice 3.

Furthermore, a known developing device using a normal or reversaldeveloping agent of a one-component system, a two-component system orthe like may be used in embodiments as the developing device 4. There isno particular limitation on toners that may be used in embodiments.

Contact type transfer charging devices using a belt, a roller, a film, arubber blade or the like, or a scorotron transfer charger or a corotrontransfer charger utilizing corona discharge may be employed as thetransfer device 5, in various embodiments.

Further, in embodiments, the cleaning device 7 may be a device forremoving a remaining toner adhered to the surface of theelectrophotographic photoreceptor 1 after a transfer step, and theelectrophotographic photoreceptor 1 repeatedly subjected to theabove-mentioned image formation process may be cleaned thereby. Inembodiments, the cleaning device 7 may be a cleaning blade, a cleaningbrush, a cleaning roll or the like. Materials for the cleaning bladeinclude urethane rubber, neoprene rubber and silicone rubber.

In the exemplary image forming device shown in FIG. 2, the respectivesteps of charging, exposure, development, transfer and cleaning areconducted in turn in the rotation step of the electrophotographicphotoreceptor 1, thereby repeatedly performing image formation. Theelectrophotographic photoreceptor 1 may be provided with specifiedsilicon-containing layers and photosensitive layers that satisfyequation (1), as described above, and thus photoreceptors havingexcellent discharge gas resistance, mechanical strength, scratchresistance, particle dispersibility, etc., may be provided. Accordingly,even in embodiments in which the photoreceptor is used together with thecontact charging device or the cleaning blade, or further with sphericaltoner obtained by chemical polymerization, good image quality can beobtained without the occurrence of image defects such as fogging. Thatis, embodiments provide image forming apparatuses that can stablyprovide good image quality for a long period of time is realized.

FIG. 3 is a cross sectional view showing another exemplary embodiment ofan image forming apparatus. The image forming apparatus 220 shown inFIG. 3 is an image forming apparatus of an intermediate transfer system,and four electrophotographic photoreceptors 401 a to 401 d are arrangedin parallel with each other along an intermediate transfer belt 409 in ahousing 400.

Here, the electrophotographic photoreceptors 401 a to 401 d carried bythe image forming apparatus 220 are each the electrophotographicphotoreceptors of embodiments. Each of the electrophotographicphotoreceptors 401 a to 401 d may rotate in a predetermined direction(counterclockwise on the sheet of FIG. 3), and charging rolls 402 a to402 d, developing device 404 a to 404 d, primary transfer rolls 410 a to410 d and cleaning blades 415 a to 415 d are each arranged along therotational direction thereof. In each of the developing device 404 a to404 d, four-color toners of yellow (Y), magenta (M), cyan (C) and black(B) contained in toner cartridges 405 a to 405 d can be supplied, andthe primary transfer rolls 410 a to 410 d are each brought into abuttingcontact with the electrophotographic photoreceptors 401 a to 401 dthrough an intermediate transfer belt 409.

Further, a laser light source (exposure unit) 403 is arranged at aspecified position in the housing 400, and it is possible to irradiatesurfaces of the electrophotographic photoreceptors 401 a to 401 d aftercharging with laser light emitted from the laser light source 403. Thisperforms the respective steps of charging, exposure, development,primary transfer and cleaning in turn in the rotation step of theelectrophotographic photoreceptors 401 a to 401 d, and toner images ofthe respective colors are transferred onto the intermediate transferbelt 409, one over the other.

The intermediate transfer belt 409 is supported with a driving roll 406,a backup roll 408 and a tension roll 407 at a specified tension, androtatable by the rotation of these rolls without the occurrence ofdeflection. Further, a secondary transfer roll 413 is arranged so thatit is brought into abutting contact with the backup roll 408 through theintermediate transfer belt 409. The intermediate transfer belt 409 whichhas passed between the backup roll 408 and the secondary transfer roll413 is cleaned up by a cleaning blade 416, and then repeatedly subjectedto the subsequent image formation process.

Further, a tray 411, for providing a medium such as paper to which atoner image is to be transferred, is provided at a specified position inthe housing 400. The medium to which the toner image is to betransferred in the tray 411 is conveyed in turn between the intermediatetransfer belt 409 and the secondary transfer roll 413, and furtherbetween two fixing rolls 414 brought into abutting contact with eachother, with a conveying roll 412, and then delivered out of the housing400.

According to the exemplary image forming apparatus 220 shown in FIG. 3,the use of electrophotographic photoreceptors of embodiments aselectrophotographic photoreceptors 401 a to 401 d may achieve dischargegas resistance, mechanical strength, scratch resistance, etc. on asufficiently high level in the image formation process of each of theelectrophotographic photoreceptors 401 a to 401 d. Accordingly, evenwhen the photoreceptors are used together with the contact chargingdevices or the cleaning blades, or further with the spherical tonerobtained by chemical polymerization, good image quality can be obtainedwithout the occurrence of image defects such as fogging. Therefore, alsoaccording to the image forming apparatus for color image formation usingthe intermediate transfer body, such as this embodiment, the imageforming apparatus which can stably provide good image quality for a longperiod of time is realized.

The above-mentioned embodiments should not be construed as limiting. Forexample, each apparatus shown in FIG. 2 or 3 may be equipped with aprocess cartridge comprising the electrophotographic photoreceptor 1 (orthe electrophotographic photoreceptors 401 a to 401 d) and chargingdevice 2 (or the charging devices 402 a to 402 d). The use of such aprocess cartridge allows maintenance to be performed more simply andeasily.

Further, in embodiments, when a charging device of the non-contactcharging system such as a corotron charger is used in place of thecontact charging device 2 (or the contact charging devices 402 a to 402d), sufficiently good image quality can be obtained.

Furthermore, in the embodiment of an apparatus that is shown in FIG. 2,a toner image formed on the surface of the electrophotographicphotoreceptor 1 is directly transferred to the medium P to which thetoner image is to be transferred. However, the image forming apparatusof embodiments may be further provided with an intermediate transferbody. This makes it possible to transfer the toner image from theintermediate transfer body to the medium P to which the toner image isto be transferred, after the toner image on the surface of theelectrophotographic photoreceptor 1 has been transferred to theintermediate transfer body. As such an intermediate transfer body, therecan be used one having a structure in which an elastic layer containinga rubber, an elastomer, a resin or the like and at least one coveringlayer are laminated on a conductive support.

In addition, the image forming apparatus of embodiments may be furtherequipped with a static eliminator such as an erase light irradiationdevice. This may prevent incorporation of residual potential intosubsequent cycles when the electrophotographic photoreceptor is usedrepeatedly. Accordingly, image quality can be more improved.

EXAMPLES

The embodiments as discussed above are illustrated in greater detailwith reference to the following Examples and Comparative Examples, butthe invention should not be construed as being limited thereto. In thefollowing examples and comparative examples, all the “parts” are givenby weight unless otherwise indicated.

Example 1 Preparation of Arylamine Intermediate

To a 1 L flask fitted with mechanical stirrer, argon inlet and refluxcondenser is charged 77.91 g (0.167 mole) Compound D (FIG. 6) in 400 mLisopropanol is slowly added two equivalents of potassium isopropoxide109.6 mL of a 19 wt. % IPA solution (0.335 mole)(commercially availablefrom Callery Chemical, Pittsburgh, Pa.). This addition provokes theinstantaneous precipitation of a white solid. The mixture is heated withstirring at just below reflux 75° for one hour. The mixture is thencooled, filtered and dried in vacuo. The yield of 90.35 g isquantitative, with the only losses being mechanical in nature. Theisolated is stable, non-hygroscopic and can easily be handled in air.

Example 2 Preparation of Arylamine Intermediate

To a 500 mLL flask fitted with mechanical stirrer, argon inlet andreflux condenser is charged 77.91 g (0.167 mole) Compound D (FIG. 6) in400 mL DMF is slowly added two equivalents of potassium isopropoxide(commercially available from Callery Chemical, Pittsburgh, Pa.). Thisaddition provokes the instantaneous precipitation of a white solid. Themixture is heated with stirring 70° for thirty minutes. The mixture isthen cooled, filtered and dried in vacuo. The yield of 90.35 g ofCompound E is quantitative, with the only losses being mechanical innature. The isolated is stable, non-hygroscopic and can easily behandled in air.

Example 3 Preparation of Arylamine Charge Transport Molecule

To a 500 mL L flask fitted with mechanical stirrer, argon inlet andreflux condenser is charged 8 g (14.76 mmol) Compound E (FIG. 6),produced in Example 1, in 140 mL DMF and 9.75 g (29.54 mmol)of3-iodopropyldiisopropoxymethylsilane (1 stoichiometric equivalent). Themixture is heated to approximately 85° C. and allowed to react withstirring for thirty minutes. The mixture is then cooled, and the crudeproduct, Compound C is obtained by toluene extraction and brine washing.Compound C has an high performance liquid chromatography purity ofapproximately 95% and, an oligomer content of from 4%, as determined bygel permeation chromatography analysis.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also,various presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art which are also intended to beencompassed by the following claims.

1. A process for forming an anhydrous alkali earth salts of adicarboxylic acid of an arylamine compound, comprising reacting adicarboxylic acid of an arylamine compound with an anhydrous alkaliearth salt.
 2. The process according to claim 1, wherein thedicarboxylic acid of an arylamine compound is a dicarboxylic acid of atertiary arylamine.
 3. The process according to claim 1, wherein theanhydrous alkali earth salt is chosen from the group consisting ofanhydrous lithium, sodium, potassium, rubidium, cesium, and franciumsalts.
 4. The process according to claim 3, wherein the anhydrous alkaliearth salt is an anhydrous potassium salt.
 5. The process according toclaim 1, wherein said reacting is conducted in a solvent.
 6. The processaccording to claim 5, wherein the solvent is chosen from the groupconsisting of DMF, methanol, ethanol, propanols, butanols, pentanols,hexanols and mixtures thereof.
 7. The process according to claim 5,wherein the solvent is DMF.
 8. The process according to claim 5, whereinthe solvent is isopropanol.
 9. The process according to claim 5, whereinsaid reacting is conducted at a temperature below a reflux temperatureof the solvent.
 10. The process according to claim 5, wherein saidreacting is conducted with stirring.
 11. The process according to claim1, wherein said reacting is carried out in a time of from about 15minutes to about 5 hours.
 12. The process according to claim 11, whereinsaid reacting is carried out in a time of from about 30 minutes to about2 hours.
 13. The process according to claim 11, wherein said reacting iscarried out in a time of about 1 hour.
 14. A process for forming asiloxane-containing hole transport molecule, comprising: reacting adicarboxylic acid of an arylamine compound with an anhydrous alkaliearth salt to form an anhydrous dicarboxylic acid salt of the arylaminecompound; and reacting said anhydrous dicarboxylic acid salt of thearylamine compound with a siloxane-containing compound.
 15. The processaccording to claim 14, wherein the dicarboxylic acid of an arylaminecompound is a dicarboxylic acid of a tertiary arylamine.
 16. The processaccording to claim 14, wherein the anhydrous alkali earth salt is chosenfrom the group consisting of anhydrous lithium, sodium, potassium,rubidium, cesium, and francium salts.
 17. The process according to claim14, wherein said reacting a dicarboxylic acid of an arylamine compoundwith an anhydrous alkali earth salt is conducted in a solvent.
 18. Theprocess according to claim 17, wherein the solvent is chosen from thegroup consisting of DMF, methanol, ethanol, propanols, butanols,pentanols, hexanols and mixtures thereof.
 19. The process according toclaim 14, wherein the siloxane-containing compound is3-iodopropyldiisopropoxymethylsilane.
 20. The process according to claim14, wherein said reacting said anhydrous dicarboxylic acid salt of thearylamine compound with a siloxane-containing compound is conducted in asolvent.
 21. The process according to claim 19, wherein the solvent isisopropanol.
 22. A silicon-containing layer for electrophotographicphotoreceptors comprising one or more siloxane-containing hole transportmolecule prepared by the process according to claim
 14. 23. Anelectrophotographic photoreceptor comprising a silicon layer, whereinthe silicon-containing layer one or more siloxane-containing holetransport molecule prepared by the process according to claim 14.